// 核心过滤：弹出栈中「≤当前元素」的数（易错点2：必须是≤，不是<）
19:16, 27 февраля 2026Бывший СССР
，更多细节参见51吃瓜
Intel documentation describes the 386's Protection Test Unit as a component that "implements fast testing of complex memory protection functions." It is mostly composed of a PLA (Programmable Logic Array), referred to as Test PLA by Intel, that is physically visible by its regular appearance on the die. This single piece of combinational logic replaces what would otherwise be dozens of multi-cycle conditional branches in the microcode. Instead of testing privilege rules sequentially, the microcode issues a single protection test operation, and the PLA evaluates all applicable rules in parallel, producing a complete decision in one evaluation: continue, fault, or redirect to a gate handler.
// 当前元素入栈：成为「左侧元素」的候选更大值（易错点4：别漏写这一步）